The present disclosure relates to a virtual reality (VR) contents streaming service and, particularly, to streaming high quality VR contents by providing image data of extended areas adjacent to a field of view (FOV) area in each image frame of the VR contents.
Virtual Reality (VR) is a technology for proving a virtual space to a user using three-dimensional (3-D) graphics, sounds and other sensations that simulate a user's physical presence in a virtual or imaginary environment and enabling the user to experience the provided virtual environment. Lately, various virtual reality (VR) devices have been introduced. The most popular VR device may be a head mounted display (HMD). In general, a VR contents streaming server may stream VR contents to such a HMD in response to a request from the HMD, and the HMD displays consecutive image frames of a field of view (FOV) area by processing the streamed VR contents. Such VR contents include a huge amount of digital data for reproducing a three-dimensional (3D) virtual space including objects in such a 3D virtual space. In particular, the VR streaming server determines a FOV area in each image frame, encodes image data of the FOV area, and transmits the encoded image data to the HMD.
When a user wearing the HMD turns a head to see other objects located outside of a FOV area (e.g., changing or switching a FOV area) by turning a head, it is necessary to request the server to redefine a new FOV area and provide image data thereof based on the changed FOV area. Accordingly, a large latency might be generated to obtain the image data of the changed FOV, and such a large latency cause motion sickness of the user.